Physical properties
Physical Properties White crystalline deliquescent powder or granules; saline and slight bitter taste; absorbs moisture from air; slowly turns brown on exposure to air due to iodine evolved; density 3.67g/cm3; melts at 660°C; vaporizes at 1,304°C; vapor pressure 1 torr at 767°C and 5 torr at 857°C; very soluble in water, 178.7 g/100 mL at 20°C and 294 g/100 mL at 70°C; soluble in ethanol and acetone.
Application
Sodium iodide was used as a component in the preparation of Mayer′s hematoxylin stain solution.
It may be used in the following processes:
Precursor in the polymerization of butyl acrylate.
Chaotropic agent in the extraction of DNA.
Deprotecting agent in the removal of N-tert-butyloxycarbonyl group in amino acids.
Water-soluble fluorescence quenching reagent.
Uses
Used as iodometric reagent
Definition
ChEBI: A metal iodide salt with a Na(+) counterion.
Definition
sodium iodide: A white crystallinesolid, NaI, very soluble in water andsoluble in both ethanol and ethanoicacid. It is known in both the anhydrousform (cubic; r.d. 3.67; m.p.661°C; b.p. 1304°C) and as the dihydrate(monoclinic; r.d. 2.45). It is preparedby the reaction of hydrogeniodide with sodium carbonate orsodium hydroxide in solution. Likepotassium iodide, sodium iodide inaqueous solution dissolves iodine toform a brown solution containingthe I3- ion. It finds applications inphotography and is also used in medicineas an expectorant and in the administrationof radioactive iodine for studies of thyroid function and fortreatment of diseases of the thyroid.
Preparation
Sodium iodide is prepared by adding hydriodic acid or an acidic iodide solution to a solution of sodium hydroxide or sodium carbonate, followed by evaporation and crystallization: NaOH + HI → NaI + H2O
The solution is filtered to remove any impurities prior to its evaporation and crystallization.
General Description
Sodium iodide is an inorganic salt. Mixture of chlorotrimethylsilane/sodium iodide in acetonitrile is a useful reagent for the cleavage of esters, lactones, carbamates and ethers.
Purification Methods
Crystallise NaI from water/ethanol solution and dry it for 12hours under vacuum, at 70o. Alternatively, dissolve it in acetone, filter it and cool it to -20o; the resulting yellow crystals are filtered off and heated in a vacuum oven at 70o for 6hours to remove acetone. The NaI is then crystallised from very dilute NaOH, dried under vacuum, and stored in a vacuum desiccator [Verdin Trans Faraday Soc 57 484 1961].
Toxics Screening Level
The ITSL for sodium iodide has been changed from 0.04 μg/m3 to 0.1 μg/m3 based on annual averaging time.
